Here at Precision Zone, we specialize in Fanuc product repairs which include a variety of power supply units. One of the many power supplies we specialize in is the A06B-6087 (A06B-6077) Alpha power supply module.

The power supply module in the Fanuc Alpha series provides main power as well as control power to other units in the chain. The power supply should always be selected depending on the capacities of the servo and spindle motors being used. A single power supply can provide power for both the spindle and servo motors, provided the capacity of the power supply is not exceeded.

Fanuc Alpha series power supplies come in 4 variations. The most common are the PSM and PSMR which are the standard power supply units. The PSM uses power regeneration during motor deceleration whereas the PSMR uses resistance regeneration. The PSMR requires an additional regenerative discharge unit. Both of these units operate at 200V/230V.

The PSM-HV is the higher voltage offering, operating at 400V/460V. This power supply is used with the higher voltage offerings of the servo and spindle units; SVM-HV and SPM-HV respectively. The fourth variation of Fanuc Alpha power supplies is the PSMV-HV; a voltage converting power supply. This unit is a 400V/460V power supply that holds the output voltage at 300VDC which allows for the PSMV-HV to be used with 200V servo and spindle drives. This is useful for when the incoming supply voltage is 400V/460V and the servos/spindles are 200V units.

When assessing the functionality of the drive, our technician's employ a basic four step troubleshooting process:

1. Visual Overview

2. Static Test

3. Checks Under Power

4. Alarm Codes Verification

This overview is Precision Zone’s basic troubleshooting process. Once our repair team starts on the job, we use specialized and customized testing fixtures, Huntron trackers, signal generators, oscilloscopes, milli and mega ohm meters, as well as any other necessary tools we have available to assure quality repair work. Most importantly, every repair is fully tested in our custom-built simulators under load with a motor to replicate real-life working environment.

Precision Zone goes as far as using heating chambers and overnight dynamic testing, when applicable, to guarantee performance of the repaired product when it arrives back with the customer.

Repair Process for Fanuc Alpha Power Supply Modules

Visual Overview

When conducting a visual check, the technician inspects the drive for any mechanical damage to the drive itself and any printed circuit boards. The technician then proceeds to verify connections are tight and correct inside the drive and there are no loose screws, wires or debris. Additionally, the unit is checked for any burn marks on the components, printed circuit boards or chassis. During the visual inspection, excessive dirt on cooling components is noted as well as the functionality of the heat sink.

Basic Static Check

Input Module Testing

Precision Zone repair technicians use digital multimeters with diode testing capabilities and also take resistance measurements to conduct a static test. For these units in particular, our team of technicians uses the diode function of the multimeter as well as huntron devices to check the input modules.

Positive Lead

Negative Lead

Reading

L1

Positive Bus Terminal

0.35V-0.39V

L2

Positive Bus Terminal

0.35V-0.39V

L3

Positive Bus Terminal

0.35V-0.39V

Negative Bus Terminal

L1

0.35V-0.39V

Negative Bus Terminal

L2

0.35V-0.39V

Negative Bus Terminal

L3

0.35V-0.39V

The capacitor values on the PCBs are verified and any relays, contactors or circuit breakers in the drive are examined to ensure proper functionality.

Checks Under Power and Alarm Code Verification

Once the unit has been statically checked and ready to be powered up, we put this power supply into our specially designed simulator. Any alarms codes are noted and subsequently repaired. Before sending the unit back to our customer, we ensure that the power supply is fully tested in our simulator and the unit is fully operational in a complete system. The Fanuc Alpha power supply has a two digit 7-segment display which indicates status and alarm codes. For an alarmed state, there is also an “ALM” LED to the left of the status display that lights up.

Common Alarms for the Fanuc Alpha Power Supply Series

Alarm Code

Description

Quick Checks

AL 1

IPM Overload, Overcurrent

Check that the fan has not failed; ensure that the fan rotates normally and is not obstructed by dirt or debris

Check motor is not causing overload

Check input supply voltage; verify it is in proper range

AL 2

Cooling Fan has stopped

Verify condition of fan

Ensure that fan rotates normally; check for any obstructions to the fan

AL 3

Heat Sink Overheat

Check operating conditions; ensure the drive is properly cooled

AL 4

DC Voltage Drop

This could be caused by a small power dip -Check incoming power

Main power has been switched off with emergency stop state released

AL 5, 6

Open phase (Input Voltage is Abnormal)

Check connections and wiring to power supply

Make sure power supply is properly rates for the SVM and SPM that are connected

Check that DC link is not short circuited

AL 7

DC Link Voltage Abnormally High

This can be caused by excessive regeneration power

Ensure that the power supply is the correctly rated capacity for the servos and spindles it is powering

For further information on these, and all other alarms, please give us a call at 800-551-4420.

Precision Zone offers free technical support on any component that you may be having issues with. We understand that when your machine goes down, your business stops. That is why our number one goal is to provide you with the best service possible so that you can get back up and running immediately. For any further product information or troubleshooting assistance is needed, please contact us via phone at 800-551-4420 or email us.

Precision Zone, Inc. is not affiliated with, nor is an authorized distributor or representative of any manufacturer, brand or product listed on this web site, with the exception of those clearly identified as such. Designated trademarks, brand names and brands, appearing herein, are the property of their respective owners.